The present invention relates to a distillation chamber for extracting solvent from sludge, in particular for dry-cleaning machines.
It is known that significant amounts of perchloroethylene are absorbed by the filtration powders during the working cycle of dry-cleaning machines.
The sludge to be treated also contains other residues of the washing operation, and the solvent content is such as to subject their storage and disposal to stringent statutory provisions and make them sometimes not only expensive but impossible.
In order to recover the perchloroethylene from the powders, it is known to subject said powders to distillation, but the efficiency of conventional systems leaves solvent residues in the powders in amounts in the range of even more than 10%.
it is also known that since at a temperature lower than 120.degree. C. the solvent does not evaporate and at temperatures above 150.degree. C. the solvent degrades, the sludge must be dried at a temperature comprised between said two values.
Furthermore, by heating the sludge to extract the perchloroethylene, sometimes the extraction temperature is reached in some regions and not in others, and a certain thickness of solid mud also stratifies on the bottom; it has been shown that it is necessary to stir the mud before and during distillation in order to operate optimally.
Furthermore, when it is necessary to remove the powders and the remaining mud at the end of extraction, the operator intervenes directly, opening the distillation chamber onto the environment and subjecting himself and said environment to pollution.
The interest in acting so as to reduce the perchloroethylene content to a level which allows the user of the washing apparatus to contract firms specialized in distillation waste treatment and which avoids contamination of the operators and of the environment, is evident.